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Wang H, Qin Y, Zhao W, Yuan T, Yang C, Mi X, Zhao P, Lu Y, Lu B, Chen Z, He Y, Yang C, Yi X, Wu Z, Chen Y, Wei Z, Huang W, Ouyang K. Genetic Characteristics and Pathogenicity of a Novel Porcine Deltacoronavirus Southeast Asia-Like Strain Found in China. Front Vet Sci 2021; 8:701612. [PMID: 34336982 PMCID: PMC8322666 DOI: 10.3389/fvets.2021.701612] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/22/2021] [Indexed: 11/13/2022] Open
Abstract
Farmers involved in the lucrative pork trading business between China and Southeast Asian countries should be aware of a recently discovered novel porcine deltacoronavirus (PDCoV) in Guangxi province, China. A PDCoV strain, CHN/GX/1468B/2017, was isolated from the small intestinal contents of piglets with diarrhea from this region, with a titer of 1 × 108.0 TCID50/mL on LLC-PK cells. The full-length genome sequence consists of 25,399 nt as determined by next-generation sequencing and this was deposited in the GenBank (accession number MN025260.1). Genomic analysis showed that CHN/GX/1468B/2017 strain had 96.9~99.4% nucleotide homology with other 87 referenced PDCoV strains from different areas, and contained 6 and 9-nt deletions at positions 1,733~1,738 and 2,804~2,812, respectively, in the ORF1a gene. Phylogenetic analyses based on the whole gene sequence as well as S protein and ORF1a/1b protein sequences all showed that this strain was closely related to the Southeast Asia strain. When 7-day-old piglets were inoculated orally with the CHN/GX/1468B/2017 strain, they developed severe diarrhea, with a peak of fecal viral shedding at 4 days post-infection. Although no death or fever were observed, the CHN/GX/1468B/2017 strain produced a wide range of tissue tropism, with the main target being the intestine. Importantly, the VH:CD ratios of the jejunum and ileum in infected piglets were significantly lower than controls. These results indicate that CHN/GX/1468B/2017, isolated in China, is a novel PDCoV Southeast Asia-like strain with distinct genetic characteristics and pathogenicity. This finding enriches the international information on the genetic diversity of PDCoV.
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Affiliation(s)
- Hejie Wang
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Yibin Qin
- Department of Virology, Guangxi Veterinary Research Institute, Nanning, China
| | - Wu Zhao
- Department of Virology, Guangxi Veterinary Research Institute, Nanning, China
| | - Tingting Yuan
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Chunjie Yang
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Xue Mi
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Ping Zhao
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Ying Lu
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Bingxia Lu
- Department of Virology, Guangxi Veterinary Research Institute, Nanning, China
| | - Zhongwei Chen
- Department of Virology, Guangxi Veterinary Research Institute, Nanning, China
| | - Ying He
- Department of Virology, Guangxi Veterinary Research Institute, Nanning, China
| | - Cui Yang
- Guangxi Key Laboratory of Livestock Genetic Improvement, Guangxi Institute of Animal Science, Nanning, China
| | - Xianfeng Yi
- Guangxi Key Laboratory of Livestock Genetic Improvement, Guangxi Institute of Animal Science, Nanning, China
| | - Zhuyue Wu
- Guangxi Key Laboratory of Livestock Genetic Improvement, Guangxi Institute of Animal Science, Nanning, China
| | - Ying Chen
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Zuzhang Wei
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Weijian Huang
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Kang Ouyang
- College of Animal Science and Technology, Guangxi University, Nanning, China
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Molecular Characterization of Porcine Epidemic Diarrhea Virus and Its New Genetic Classification Based on the Nucleocapsid Gene. Viruses 2020; 12:v12080790. [PMID: 32717934 PMCID: PMC7472284 DOI: 10.3390/v12080790] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/19/2020] [Accepted: 07/21/2020] [Indexed: 11/17/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) causes continuous, significant damage to the swine industry worldwide. By RT-PCR-based methods, this study demonstrated the ongoing presence of PEDV in pigs of all ages in Korea at the average detection rate of 9.92%. By the application of Bayesian phylogenetic analysis, it was found that the nucleocapsid (N) gene of PEDV could evolve at similar rates to the spike (S) gene at the order of 10-4 substitutions/site/year. Based on branching patterns of PEDV strains, three main N gene-base genogroups (N1, N2, and N3) and two sub-genogroups (N3a, N3b) were proposed in this study. By analyzing the antigenic index, possible antigenic differences also emerged in both the spike and nucleocapsid proteins between the three genogroups. The antigenic indexes of genogroup N3 strains were significantly lower compared with those of genogroups N1 and N2 strains in the B-cell epitope of the nucleocapsid protein. Similarly, significantly lower antigenic indexes in some parts of the B-cell epitope sequences of the spike protein (COE, S1D, and 2C10) were also identified. PEDV mutants derived from genetic mutations of the S and N genes may cause severe damage to swine farms by evading established host immunities.
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Characterization and Pathogenicity of the Porcine Deltacoronavirus Isolated in Southwest China. Viruses 2019; 11:v11111074. [PMID: 31752115 PMCID: PMC6893596 DOI: 10.3390/v11111074] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 12/16/2022] Open
Abstract
Porcine deltacoronavirus (PDCoV) is a newly emerging enteric pathogen in swine that causes diarrhea in neonatal piglets and creates an additional economic burden on porcine industries in Asia and North America. In this study, a PDCoV isolate, CHN-SC2015, was isolated from Sichuan Province in southwest China. The isolate was characterized by a cytopathic effect, immunofluorescence, and electron microscopy. CHN-SC2015 titers in LLC-PK cells ranged from 104.31 to 108.22 TCID50/mL during the first 30 passages. During serial passage, 11 nucleotide mutations occurred in the S gene, resulting in nine amino acid changes. A whole genome sequencing analysis demonstrated that CHN-SC2015 shares 97.5%-99.1% identity with 59 reference strains in GenBank. Furthermore, CHN-SC2015 contained 6-nt deletion and 9-nt insertion in the ORF1ab gene, 3-nt deletion in the S gene and 11-nt deletion in its 3'UTR compared with other reference strains available in GenBank. A phylogenetic analysis showed that CHN-SC2015 is more closely related to other PDCoV strains in China than to the strains from Southeast Asia, USA, Japan, and South Korea, indicating the diversity of genetic relationships and regional and epidemic characteristics among these strains. A recombination analysis indicated that CHN-SC2015 experienced recombination events between SHJS/SL/2016 and TT-1115. In vivo infection demonstrated that CHN-SC2015 is highly pathogenic to sucking piglets, causing diarrhea, vomiting, dehydration, and death. Virus was shed daily in the feces of infected piglets and upon necropsy, was found distributed in the gastrointestinal tract and in multiple organs. CHN-SC2015 is the first systematically characterized strain from southwest China hitherto reported. Our results enrich the body of information on the epidemiology, pathogenicity and molecular evolution associated with PDCoV.
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Gu WY, Li Y, Liu BJ, Wang J, Yuan GF, Chen SJ, Zuo YZ, Fan JH. Short hairpin RNAs targeting M and N genes reduce replication of porcine deltacoronavirus in ST cells. Virus Genes 2019; 55:795-801. [PMID: 31463771 PMCID: PMC7088929 DOI: 10.1007/s11262-019-01701-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 08/14/2019] [Indexed: 12/22/2022]
Abstract
Porcine deltacoronavirus (PDCoV) is a recently identified coronavirus that causes intestinal diseases in neonatal piglets with diarrhea, vomiting, dehydration, and post-infection mortality of 50–100%. Currently, there are no effective treatments or vaccines available to control PDCoV. To study the potential of RNA interference (RNAi) as a strategy against PDCoV infection, two short hairpin RNA (shRNA)-expressing plasmids (pGenesil-M and pGenesil-N) that targeted the M and N genes of PDCoV were constructed and transfected separately into swine testicular (ST) cells, which were then infected with PDCoV strain HB-BD. The potential of the plasmids to inhibit PDCoV replication was evaluated by cytopathic effect, virus titers, and real-time quantitative RT-PCR assay. The cytopathogenicity assays demonstrated that pGenesil-M and pGenesil-N protected ST cells against pathological changes with high specificity and efficacy. The 50% tissue culture infective dose showed that the PDCoV titers in ST cells treated with pGenesil-M and pGenesil-N were reduced 13.2- and 32.4-fold, respectively. Real-time quantitative RT-PCR also confirmed that the amount of viral RNA in cell cultures pre-transfected with pGenesil-M and pGenesil-N was reduced by 45.8 and 56.1%, respectively. This is believed to be the first report to show that shRNAs targeting the M and N genes of PDCoV exert antiviral effects in vitro, which suggests that RNAi is a promising new strategy against PDCoV infection.
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Affiliation(s)
- Wen-yuan Gu
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, 071001 People’s Republic of China
- Animal Diseases Control Center of Hebei, Shijiazhuang, 050053 China
| | - Yan Li
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, 071001 People’s Republic of China
| | - Bao-jing Liu
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, 071001 People’s Republic of China
| | - Jing Wang
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, 071001 People’s Republic of China
| | - Guang-fu Yuan
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, 071001 People’s Republic of China
| | - Shao-jie Chen
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, 071001 People’s Republic of China
| | - Yu-Zhu Zuo
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, 071001 People’s Republic of China
| | - Jing-Hui Fan
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, 071001 People’s Republic of China
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Lin H, Zhou H, Gao L, Li B, He K, Fan H. Development and application of an indirect ELISA for the detection of antibodies to porcine epidemic diarrhea virus based on a recombinant spike protein. BMC Vet Res 2018; 14:243. [PMID: 30126390 PMCID: PMC6102851 DOI: 10.1186/s12917-018-1570-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 08/13/2018] [Indexed: 12/13/2022] Open
Abstract
Background As the major causative agent of swine viral diarrhea, porcine epidemic diarrhea virus (PEDV) has caused massive losses to the economies of swine raising countries. Accordingly, the serological detection of corresponding antibodies would be beneficial to diagnose PEDV indirectly to control the disease. In this study, an indirect enzyme-linked immunosorbent assay (ELISA) based on the recombinant truncated spike (S) protein of PEDV was developed and validated. Results The reaction conditions of the developed indirect ELISA were optimized. This indirect ELISA was compared to indirect immunoinfluscent assay (IFA), and the overall coincidence rate was 96.74% based on testing 368 clinical serum samples with different PEDV antibody levels. No cross-reactivity with other common swine pathogens was detected for the developed S1 indirect ELISA. Finally, the S1 indirect ELISA was applied to detect serum antibodies of 3304 field samples collected from different pig farms in eastern China, and it presented an overall substantial agreement on the PEDV infection status. Conclusions This established S1 indirect ELISA is capable of detecting serum antibodies against PEDV, and due to its high sensitivity and specificity, it could be applied for serological evaluation and indirect diagnosis of PEDV infection.
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Affiliation(s)
- Huixing Lin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Hong Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Lu Gao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China
| | - Bin Li
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Kongwang He
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China. .,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China.
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Liu BJ, Zuo YZ, Gu WY, Luo SX, Shi QK, Hou LS, Zhong F, Fan JH. Isolation and phylogenetic analysis of porcine deltacoronavirus from pigs with diarrhoea in Hebei province, China. Transbound Emerg Dis 2018; 65:874-882. [PMID: 29363288 PMCID: PMC7169788 DOI: 10.1111/tbed.12821] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Indexed: 12/11/2022]
Abstract
Porcine deltacoronavirus (PDCoV) is a recently identified coronavirus in the genus Deltacoronavirus that can cause enteric disease with clinical signs including diarrhoea, vomiting, dehydration and mortality in neonatal piglets. Although evidence of the prevalence of PDCoV in China is accumulating, little published information about Chinese PDCoV isolates is available. In this study, we investigated the presence of PDCoV in 49 faecal/intestinal samples from piglets with diarrhoea on different farms in Hebei province. Five samples (10.2%) were positive for PDCoV, but no coinfection of PDCoV with other enteropathogens was observed. A PDCoV strain named HB-BD was successfully isolated from the intestinal contents of a diarrhoeic piglet and serially propagated in swine testicular (ST) cells for >40 passages. The complete genome of the HB-BD strain was sequenced and analysed. Genomic analysis showed that the HB-BD strain had a closer relationship with Chinese strains than those from other countries and was grouped within the Chinese PDCoV cluster. The results of this study will be valuable for further research of PDCoV genetic evolution and development of effective diagnostic reagents, assays and potential vaccines against newly emerged PDCoV strains.
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Affiliation(s)
- B-J Liu
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, China
| | - Y-Z Zuo
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, China.,College of Animal Science and Technology, Agricultural University of Hebei, Baoding, China
| | - W-Y Gu
- Animal Diseases Control Center of Hebei, Shijiazhuang, China
| | - S-X Luo
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, China
| | - Q-K Shi
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, China
| | - L-S Hou
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, China
| | - F Zhong
- College of Animal Science and Technology, Agricultural University of Hebei, Baoding, China
| | - J-H Fan
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding, China
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Lei X, Zhao J, Wang X, Zhao Y, Wang C. Development of a hybridoma cell line secreting monoclonal antibody against S protein of a Chinese variant of PEDV. Monoclon Antib Immunodiagn Immunother 2015; 34:12-6. [PMID: 25723278 DOI: 10.1089/mab.2014.0063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Gene encoding 22-380 aa of spike protein of porcine epidemic diarrhea virus (PEDV) isolate in China was cloned and expressed as a recombinant protein in Escherichia coli BL21(DE3). Female BALB/c mice were immunized with the purified recombinant S protein, and a monoclonal antibody (MAb) designated as 2D1 against S protein was achieved by hybridoma technique. MAb 2D1 reacted with S protein of PEDV specifically. The monoclonal antibody 2D1 may provide a useful tool as a specific diagnostic reagent for detecting S protein of the Chinese variant of PEDV and for further investigation into the virus' pathogenic mechanism.
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Affiliation(s)
- Ximei Lei
- College of Animal Science and Veterinary Medicine, Henan Agricultural University , Zhengzhou, China
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Shen H, Zhang C, Guo P, Liu Z, Zhang J. Effective inhibition of porcine epidemic diarrhea virus by RNA interference in vitro. Virus Genes 2015; 51:252-9. [PMID: 26329934 PMCID: PMC7088742 DOI: 10.1007/s11262-015-1242-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/20/2015] [Indexed: 11/25/2022]
Abstract
Porcine epidemic diarrhea virus (PEDV) is a member of the coronaviridae family, which can cause acute and highly contagious enteric disease of swine characterized by severe entero-pathogenic diarrhea in piglets. Currently, the vaccines of PEDV are only partially effective and there is no specific drug available for treatment of PEDV infection. To exploit the possibility of using RNA interference (RNAi) as a strategy against PEDV infection, five shRNA-expressing plasmids targeting the N, M, and S genes of PEDV were constructed and transfected into Vero cells. The cytopathic effect and MTS assays demonstrated that two shRNAs (pSilencer4.1-M1 and pSilencer4.1-N) were capable of protecting cells against PEDV invasion with very high specificity and efficiency. The two shRNA expression plasmids were also able to inhibit the PEDV replication significantly, as shown by detection of virus titers (TCID50/mL). A real-time quantitative RT-PCR further confirmed that the amounts of viral RNAs in cell cultures pre-transfected with these two plasmids were reduced by 95.0 %. Our results suggest that RNAi might be a promising new strategy against PEDV infection.
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Affiliation(s)
- Haiyan Shen
- Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangdong Open Laboratory of Veterinary Public Health, Guangdong Provincial Key Laboratory of Livestock Disease Prevention, Guangzhou, 510640, Guangdong, China
| | - Chunhong Zhang
- Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangdong Open Laboratory of Veterinary Public Health, Guangdong Provincial Key Laboratory of Livestock Disease Prevention, Guangzhou, 510640, Guangdong, China
| | - Pengju Guo
- Guangdong Laboratory Animals Monitoring Institute, Guangzhou, 510640, Guangdong, China
| | - Zhicheng Liu
- Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangdong Open Laboratory of Veterinary Public Health, Guangdong Provincial Key Laboratory of Livestock Disease Prevention, Guangzhou, 510640, Guangdong, China
| | - Jianfeng Zhang
- Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangdong Open Laboratory of Veterinary Public Health, Guangdong Provincial Key Laboratory of Livestock Disease Prevention, Guangzhou, 510640, Guangdong, China.
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Fan JH, Zuo YZ, Shen XQ, Gu WY, Di JM. Development of an enzyme-linked immunosorbent assay for the monitoring and surveillance of antibodies to porcine epidemic diarrhea virus based on a recombinant membrane protein. J Virol Methods 2015; 225:90-4. [PMID: 26253335 PMCID: PMC7119585 DOI: 10.1016/j.jviromet.2015.07.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 07/31/2015] [Accepted: 07/31/2015] [Indexed: 12/05/2022]
Abstract
Expressed membrane protein of porcine epidemic diarrhea virus in Escherichia coli. An indirect ELISA was developed using purified recombinant M protein as detection antigen. Assessing fit for immunologic surveillance and sero-diagnosis of PEDV. The developed iELISA is specific, sensitive and does not require PEDV cultivation. This iELISA could be used for large-scale serological testing.
The recent dramatic increase in reported cases of porcine epidemic diarrhea (PED) in pig farms is a potential threat to the global swine industry. Therefore, the accurate diagnosis, serological monitoring, and surveillance of specific antibodies in pigs resulting from porcine epidemic diarrhea virus (PEDV) infection or vaccination would be essential in helping to control the spread of PED. We developed and validated an indirect enzyme-linked immunosorbent assay (ELISA) based on the recombinant membrane (M) protein of PEDV. To detect PEDV antibodies in eight herds, 382 serum samples were collected from sows that had been immunized with a PED vaccine, and screened using the developed ELISA in parallel with a serum neutralization (SN) assay. Of the tested samples, 276 were positive for the presence of PEDV antibodies according to both assays, while 98 were negative. An excellent agreement between the ELISA and the SN assay was observed (kappa = 0.947; 95% confidence interval = 0.910–0.984; McNemar's test, P = 0.727). No cross-reaction was detected for the developed ELISA with other coronaviruses or other common pig pathogens. The developed ELISA could be used for serological evaluation and indirect diagnosis of PED infection.
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Affiliation(s)
- Jing-Hui Fan
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding 071001, People's Republic of China
| | - Yu-Zhu Zuo
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding 071001, People's Republic of China.
| | - Xiao-Qiang Shen
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding 071001, People's Republic of China
| | - Wen-Yuan Gu
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding 071001, People's Republic of China
| | - Jing-Mei Di
- College of Veterinary Medicine, Agricultural University of Hebei, Baoding 071001, People's Republic of China
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Huan CC, Wang Y, Ni B, Wang R, Huang L, Ren XF, Tong GZ, Ding C, Fan HJ, Mao X. Porcine epidemic diarrhea virus uses cell-surface heparan sulfate as an attachment factor. Arch Virol 2015; 160:1621-8. [PMID: 25896095 DOI: 10.1007/s00705-015-2408-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/26/2015] [Indexed: 10/23/2022]
Abstract
It is well known that many viruses use heparan sulfate as the initial attachment factor. In the present study, we determined whether porcine epidemic diarrhea virus (PEDV), an emerging veterinary virus, infects Vero cells by attaching to heparan sulfate. Western blot analysis, real-time PCR, and plaque formation assay revealed that PEDV infection was inhibited when the virus was pretreated with heparin (an analogue of heparan sulfate). There was no inhibitory effect when the cells were pre-incubated with heparin. We next demonstrated that enzymatic removal of the highly sulfated domain of heparan sulfate by heparinase I treatment inhibited PEDV infection. We also confirmed that sodium chlorate, which interferes with heparan sulfate biosynthesis, also inhibited PEDV infection. Furthermore, we examined the effect of two heparin derivatives with different types of sulfation on PEDV infection. The data suggested de-N-sulfated heparin, but not N-acetyl-de-O-sulfated heparin, inhibits PEDV infection. In summary, our studies revealed that heparan sulfate acts as the attachment factor of PEDV in Vero cells.
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Affiliation(s)
- Chang-chao Huan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, China
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Abstract
In the last decade, many porcine epidemic diarrhoea (PED) outbreaks have been reported by several countries in Asia whereas only a few Member States of the European Union (EU) have reported PED clinical cases and/or PED virus (PEDV)-seropositive animals. This alphacoronavirus was first reported in the USA in May 2013, followed by rapid spread throughout the country and outbreaks reported by several countries in the Americas. The recent PEDV-EU isolates have high level of sequence identity to PEDV-Am isolates. Based on nucleotide sequencing, multiple variants of PEDV are circulating in Europe, the Americas and Asia but any difference in virulence and antigenicity is currently unknown. Serological cross-reactivity has been reported between PEDV isolated in Europe and in the Americas; however no data regarding cross-protection are available. The impact of different PEDV strains is difficult to compare between one country and another, since impact is dependent not only on pathogenicity but also on factors such as biosecurity, farm management, sanitary status or herd immune status. However, the clinical signs of PEDV infections in naive pigs are similar in different countries with mortalities up to 100% in naive newborn piglets. The impact of recently reported PED outbreaks in Asia and the USA seems to be more severe than what has been described in Europe. Infected animals, faeces, feed and objects contaminated with faeces are matrices that have been reported to transmit PEDV between farms. Infectious PEDV has been detected in spray-dried porcine plasma (SDPP) in one study but the origin of the infectious PEDV in SDPP is not clear. Detection of porcine deltacoronavirus (PDCoV) has been reported in a few countries but only limited testing has been done. Based on the currently available information, it seems that PDCoV would have a lower impact than PEDV.
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Hao J, Xue C, He L, Wang Y, Cao Y. Bioinformatics insight into the spike glycoprotein gene of field porcine epidemic diarrhea strains during 2011-2013 in Guangdong, China. Virus Genes 2014; 49:58-67. [PMID: 24771495 PMCID: PMC7088867 DOI: 10.1007/s11262-014-1055-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 03/06/2014] [Indexed: 10/27/2022]
Abstract
Three strains of porcine epidemic diarrhea virus (PEDV) were isolated from dead or diseased pigs at different swine farms in Guangdong during 2011-2013, and their S genes were sequenced. In the same period, seven PEDV strains were also isolated in Guangdong by other laboratories. The spike sequences of 10 Guangdong isolates were compared with vaccine strains and reference pathogenic isolates using six bioinformatics tools. The results revealed that 10 Guangdong strains, excluding strain GDS03, had distinct characteristics in terms of primary structure, secondary structure, high-specificity N-glycosylation sites, potential phosphorylation sites, and palmitoylation sites. Phylogenetic analysis also confirmed these findings and revealed that all PEDV strains were clustered into three distinct groups. Ten Guangdong strains, not including GDS03, belong to Group 1, whereas four vaccine strains and GDS03 belong to Group 3, which is evolutionarily distant from Group 1. Alignment analysis of the neutralizing region amino acid sequences indicated that the amino acid substitutions of Y/D766S, T549S, and G594S that are present in the Guangdong strains, not including GDS03, were a sign of predominant genetic changes among the isolated strains. GDS03 is closely related to the 83P-5 vaccine strain, which suggests that it might represent re-isolation of the vaccine strain or vaccine variants. Taken together, these results indicate that there have been predominant new strains circulating in Guangdong from 2011 to 2013, and the circulating PEDV strains have a genetic composition that is distant from reference strains, especially the vaccine strains; however, the vaccinations might also provide some level of cross-protection, as there have been no changes in the neutralizing epitopes of SS2 and 2C10. This explains why there have been constant but infrequent outbreaks recently in comparison to late 2010 in which PEDV outbreaks were more frequent and severe. In addition, the USA-Colorado-2013 strain had the same amino acid substitutions in the neutralizing regions as the Guangdong strains except GDS03, which suggests that the information and strategies in this study may play role in PEDV variant research in other countries.
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Affiliation(s)
- Jianwei Hao
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006 People’s Republic of China
| | - Chunyi Xue
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006 People’s Republic of China
| | - Liangliang He
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006 People’s Republic of China
| | - Yang Wang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006 People’s Republic of China
| | - Yongchang Cao
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006 People’s Republic of China
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Isolation and characterization of porcine epidemic diarrhea viruses associated with the 2013 disease outbreak among swine in the United States. J Clin Microbiol 2013; 52:234-43. [PMID: 24197882 DOI: 10.1128/jcm.02820-13] [Citation(s) in RCA: 309] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) was detected in May 2013 for the first time in U.S. swine and has since caused significant economic loss. Obtaining a U.S. PEDV isolate that can grow efficiently in cell culture is critical for investigating pathogenesis and developing diagnostic assays and for vaccine development. An additional objective was to determine which gene(s) of PEDV is most suitable for studying the genetic relatedness of the virus. Here we describe two PEDV isolates (ISU13-19338E and ISU13-22038) successfully obtained from the small intestines of piglets from sow farms in Indiana and Iowa, respectively. The two isolates have been serially propagated in cell culture for over 30 passages and were characterized for the first 10 passages. Virus production in cell culture was confirmed by PEDV-specific real-time reverse-transcription PCR (RT-PCR), immunofluorescence assays, and electron microscopy. The infectious titers of the viruses during the first 10 passages ranged from 6 × 10(2) to 2 × 10(5) 50% tissue culture infective doses (TCID50)/ml. In addition, the full-length genome sequences of six viruses (ISU13-19338E homogenate, P3, and P9; ISU13-22038 homogenate, P3, and P9) were determined. Genetically, the two PEDV isolates were relatively stable during the first 10 passages in cell culture. Sequences were also compared to those of 4 additional U.S. PEDV strains and 23 non-U.S. strains. All U.S. PEDV strains were genetically closely related to each other (≥99.7% nucleotide identity) and were most genetically similar to Chinese strains reported in 2011 to 2012. Phylogenetic analyses using different genes of PEDV suggested that the full-length spike gene or the S1 portion is appropriate for sequencing to study the genetic relatedness of these viruses.
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Sequence heterogeneity of the ORF3 gene of porcine epidemic diarrhea viruses field samples in Fujian, China, 2010-2012. Viruses 2013; 5:2375-83. [PMID: 24084234 PMCID: PMC3814593 DOI: 10.3390/v5102375] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/13/2013] [Accepted: 09/19/2013] [Indexed: 11/16/2022] Open
Abstract
Twenty-seven field samples that showed positive in PEDV detection were collected from different farms of Fujian province from 2010 to 2012. Their heterogeneity was investigated by analysis of the ORF3 gene because of its potential function as a representation of virulence. According to the results, six Fujian strains in Group 1 showed a different genotype with unique point mutations, which might be used in differentiation between PEDV groups and brought potential antigenic variation. P55 and five reference strains in Group 2 had a long length deletion, showing another genotype and might be involved in the variation of virulence. Phylogenetic analysis revealed that the collected Fujian strains were very distant from the vaccine development strain CV777, which might be the reason why the vaccine was inefficient to control the disease. The results can help to reconsider the strategy of PEDV vaccine management and prevent outbreaks of PEDV-induced diarrhea more efficiently.
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Sequence and phylogenetic analysis of nucleocapsid genes of porcine epidemic diarrhea virus (PEDV) strains in China. Arch Virol 2013; 158:1267-73. [PMID: 23389550 PMCID: PMC3668129 DOI: 10.1007/s00705-012-1592-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 11/29/2012] [Indexed: 11/23/2022]
Abstract
Porcine epidemic diarrhea virus (PEDV) causes acute diarrhea and dehydration with high mortality rates in swine. It has become increasingly problematic in China. Since the nucleocapsid (N) protein is highly conserved, it is a candidate protein for early diagnosis and vaccine development. In this study, the N genes of 15 PEDV strains were amplified by RT-PCR and cloned into the pMT-19T vector, sequenced, and compared to each other as well as to PEDV reference strains. The nucleotide sequences of the N gene of the Chinese PEDV strains consist of 1326 nucleotides and encode a 441-aa-long peptide. The nucleotide sequences of the fifteen PEDV strains in our study were 96.1-100 % identical to each other, and the deduced amino acid sequences were 94.8-100 % identical. Sequence comparison with other PEDV strains selected from GenBank revealed that their nucleotide sequences were 94.2-99.7 % identical to those of the Chinese PEDV strains, and their deduced amino acid sequences were 94.1-99.5 % identical. In addition, the fifteen strains showed a high degree of nucleotide sequence identity to the early domestic strains (98.4-99.7 %) except the LZC strain, but less sequence identity to the vaccine strain (CV777) used in China (94.7-97.7 %). Phylogenetic analysis showed that the Chinese PEDV strains are composed of a separate cluster including three early domestic strains (JS-2004-02, LJB/03 and DX) but differ genetically from the vaccine strain (CV777) and the early Korean strains (Chinju99 and SM98).
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Complete genome sequence of novel porcine epidemic diarrhea virus strain GD-1 in China. J Virol 2013; 86:13824-5. [PMID: 23166239 DOI: 10.1128/jvi.02615-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Porcine epidemic diarrhea virus (PEDV) infection, which causes acute diarrhea and dehydration in suckling piglets, has become a serious problem for the swine industry of China in recent years. In this study, a virulent PEDV strain, GD-1, was obtained from fecal samples from suckling piglets that suffered from severe diarrhea in 2011 in Guangdong, China. Here we describe the complete genome sequence of strain GD-1, which may be helpful in further understanding the molecular epidemiology and genetic diversity of PEDV field isolates in China.
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Fan JH, Zuo YZ, Ren XF. Progress in research of genetic characteristics of porcine epidemic diarrhea virus and diagnostic methods for porcine epidemic diarrhea. Shijie Huaren Xiaohua Zazhi 2013; 21:54-59. [DOI: 10.11569/wcjd.v21.i1.54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Porcine epidemic diarrhea (PED), caused by PED virus (PEDV), is a devastating contagious viral swine disease that is characterized by acute enteritis and lethal watery diarrhea. In Asia (such as Korea, Japan, and China), PEDV causes a very high mortality in suckling piglets. Some affected farms lost 100% of newborn piglets. PED can hardly be distinguished from transmissible gastroenteritis clinically and histopathologically. Identification of the causal agent is a basic prerequisite both for introduction of immunoprophylactic measures and for evaluation of prevention measures. Therefore, rapid differential diagnosis of PED and TGE is important. The purpose of the current review is to describe the molecular and genetic characteristics of PEDV, and discuss the diagnosis methods for PED.
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Complete genome sequence of a novel porcine epidemic diarrhea virus in south China. J Virol 2012; 86:10248-9. [PMID: 22923806 DOI: 10.1128/jvi.01589-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Since early 2010, outbreaks of porcine epidemic diarrhea (PED) have been observed frequently in immunized swine herds in southern China. The suckling piglets are particularly susceptible to porcine epidemic diarrhea virus (PEDV), with a high mortality rate (90%). Recently, a virulent PEDV strain, GD-A, was isolated from an immunized-swine breeding farm in Guangdong, China. This report describes the complete genome sequence of GD-A, and the data will provide important insights into the variation of PEDV field isolates in southern China.
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